1Version 2.11 September 13, 2017
2
3A Partial List of Missing Features
4==================================
5
6Contributions are welcome.  There are plenty of opportunities
7for visible, important contributions to this module.  Here
8is a partial list of the known problems and missing features:
9
10a) SMB3 (and SMB3.02) missing optional features:
11   - multichannel (started), integration with RDMA
12   - directory leases (improved metadata caching), started (root dir only)
13   - T10 copy offload ie "ODX" (copy chunk, and "Duplicate Extents" ioctl
14     currently the only two server side copy mechanisms supported)
15
16b) improved sparse file support
17
18c) Directory entry caching relies on a 1 second timer, rather than
19using Directory Leases, currently only the root file handle is cached longer
20
21d) quota support (needs minor kernel change since quota calls
22to make it to network filesystems or deviceless filesystems)
23
24e) Compounding (in progress) to reduce number of roundtrips, and also
25better optimize open to reduce redundant opens (using reference counts more).
26
27f) Finish inotify support so kde and gnome file list windows
28will autorefresh (partially complete by Asser). Needs minor kernel
29vfs change to support removing D_NOTIFY on a file.
30
31g) Add GUI tool to configure /proc/fs/cifs settings and for display of
32the CIFS statistics (started)
33
34h) implement support for security and trusted categories of xattrs
35(requires minor protocol extension) to enable better support for SELINUX
36
37i) Add support for tree connect contexts (see MS-SMB2) a new SMB3.1.1 protocol
38   feature (may be especially useful for virtualization).
39
40j) Create UID mapping facility so server UIDs can be mapped on a per
41mount or a per server basis to client UIDs or nobody if no mapping
42exists. Also better integration with winbind for resolving SID owners
43
44k) Add tools to take advantage of more smb3 specific ioctls and features
45(passthrough ioctl/fsctl for sending various SMB3 fsctls to the server
46is in progress)
47
48l) encrypted file support
49
50m) improved stats gathering, tools (perhaps integration with nfsometer?)
51
52n) allow setting more NTFS/SMB3 file attributes remotely (currently limited to compressed
53file attribute via chflags) and improve user space tools for managing and
54viewing them.
55
56o) mount helper GUI (to simplify the various configuration options on mount)
57
58p) Add support for witness protocol (perhaps ioctl to cifs.ko from user space
59   tool listening on witness protocol RPC) to allow for notification of share
60   move, server failover, and server adapter changes.  And also improve other
61   failover scenarios, e.g. when client knows multiple DFS entries point to
62   different servers, and the server we are connected to has gone down.
63
64q) Allow mount.cifs to be more verbose in reporting errors with dialect
65or unsupported feature errors.
66
67r) updating cifs documentation, and user guide.
68
69s) Addressing bugs found by running a broader set of xfstests in standard
70file system xfstest suite.
71
72t) split cifs and smb3 support into separate modules so legacy (and less
73secure) CIFS dialect can be disabled in environments that don't need it
74and simplify the code.
75
76v) POSIX Extensions for SMB3.1.1 (started, create and mkdir support added
77so far).
78
79KNOWN BUGS
80====================================
81See http://bugzilla.samba.org - search on product "CifsVFS" for
82current bug list.  Also check http://bugzilla.kernel.org (Product = File System, Component = CIFS)
83
841) existing symbolic links (Windows reparse points) are recognized but
85can not be created remotely. They are implemented for Samba and those that
86support the CIFS Unix extensions, although earlier versions of Samba
87overly restrict the pathnames.
882) follow_link and readdir code does not follow dfs junctions
89but recognizes them
90
91Misc testing to do
92==================
931) check out max path names and max path name components against various server
94types. Try nested symlinks (8 deep). Return max path name in stat -f information
95
962) Improve xfstest's cifs/smb3 enablement and adapt xfstests where needed to test
97cifs/smb3 better
98
993) Additional performance testing and optimization using iozone and similar -
100there are some easy changes that can be done to parallelize sequential writes,
101and when signing is disabled to request larger read sizes (larger than
102negotiated size) and send larger write sizes to modern servers.
103
1044) More exhaustively test against less common servers
105